Trillium ovatum, commonly known as the Western trillium, is an herbaceous monocot and a member of the Liliaceae family. It is native to the North American west coast including southern British Columbia, Washington, Oregon, and Northern California, as well as Colorado, Wyoming, Idaho, Montana, and parts of Alberta. Western trillium typically grows to a height of 10 to 20 cm. The green leaves are ovate, between
5 and 15 cm in length, and grow in a flat whorl of three under the flower (Alden 1998).The flower is white but turns pinkish or reddish as it ages. The peduncle is between 2 and 8 cm long. What makes T. ovatum unique is that the sepals grow in a whorl of three and are narrowly oblong, alternating with the three white petals of the flower. The fruit is a yellowish oval-shaped capsule with small seeds (Legler, et al 2018; Pojar and Mackinnon 2004).
This species is found exclusively in temperate climates. It thrives in soil that is pH neutral-acidic, rich in nutrients, at least partially shaded, and moist. It is a perennial with four main stages of life: cotyledon, one-leaved, three-leaved, and three-leaved with flower (Rottink 2016). It usually reaches its flowering stage during late April and will remain in this stage until June. Then the plant regresses to its “three-leaved” stage until the following spring.
T. ovatum is an edible plant and has been used in some medical practices. Its seeds and leaves are most commonly consumed. The seeds are compared to sunflower seeds. Various Native American groups have used preparations of the plant’s roots to treat afflictions of the eyes and boils on the skin (NAED 2003).
Western trillium has a symbiotic relationship with ants and an interesting association with robins. Once a trillium seed is ready to be pollinated, it produces an oil reservoir that attracts ants. The ants then carry the seed back to their nest and feed on the oil where the plant then grows.The ants use the seed to feed larvae. This is an effective mechanism for seed dispersal because ants are responsible for 30% of the spring-flowering of herbaceous plants in eastern United States forests, as well as a number of species in western forests (Pojar and Mackinnon 2004). Also, as the flower blooms in early spring, between March and May, robins start to appear. This has led to the alternative name for Trillium ovatum, which is “wake-robin,” because the flowers were thought to wake up the birds for springtime (Pojar and McKinnon 2004).
Trillium ovatum, the Pacific trillium, also known as the western wakerobin, western white trillium, or western trillium, is a species of flowering plant in the family Melanthiaceae.[1][4][5][6] It is found in western North America, from southern British Columbia and the tip of southwestern Alberta to central California, east to Idaho and western Montana. There is an isolated population in northern Colorado and southern Wyoming.[7]
T. ovatum is the most widespread and abundant trillium in western North America.[8] It is the only pedicellate-flowered Trillium species found within its range.[9] The type specimen for this species was gathered by Meriwether Lewis in 1806 along the Columbia River during the return trip of the Lewis and Clark Expedition.[10]
The most widespread of the western North American trilliums, Trillium ovatum varies greatly within its range. Despite this, T. ovatum closely resembles the eastern T. grandiflorum. Apart from geographic location, the two species are not easily distinguished.[11]
T. ovatum is a perennial herbaceous plant that spreads by means of underground rhizomes. At maturity, each plant has one or two flowering scapes, each 20 to 50 cm (8 to 19.5 in) in length. The specific epithet ovatum means “egg-shaped,” which refers to the petals, not the leaves. The latter are generally ovate-rhombic, 7 to 12 cm (3 to 5 in) long by 5 to 20 cm (2 to 8 in) wide.[4]
The flower sits on a pedicel 2 to 6 cm (1 to 2.5 in) in length. The sepals are 15 to 50 mm (0.59 to 1.97 in) long and 6 to 20 mm (0.24 to 0.79 in) wide, while the petals are 15 to 70 mm (0.59 to 2.76 in) long and 10 to 40 mm (0.39 to 1.57 in) wide. Typically the flower opens white and becomes pink with age, but in the Smith River Canyon area of northern California and southern Oregon, the petals become almost barn-red.[12]
Supported by thin white filaments, the yellow anthers are 4–16 mm long
The flower starts white, but often becomes pink as it matures
In addition to Trillium ovatum Pursh, the following infraspecific taxa are accepted by the World Checklist of Selected Plant Families:[13]
The variety T. o. var. oettingeri is endemic to the Salmon Mountains of northwestern California and hence Oettinger's trillium is known as the Salmon Mountains wakerobin.[14] Unlike the nominate variety T. o. var. ovatum, the variety oettingeri has leaves with short petioles and linear flower petals.[15][16][17]
Trillium ovatum f. maculosum Case & R.B.Case refers to a form with mottled leaves that occurs in Mendocino County, California. This is the only reported instance of mottled leaves in a pedicellate Trillium.[18][16]
The names Trillium ovatum f. hibbersonii T.M.C.Taylor & Szczaw. and T. o. var. hibbersonii (T.M.C.Taylor & Szczaw.) G.W.Douglas & Pojar are synonyms for T. hibbersonii (T.M.C.Taylor & Szczaw.) D.O'Neill & S.B.Farmer,[19] a member of the Erectum group. Despite its provenance, T. hibbersonii is no longer thought to be related to T. ovatum.[20][21]
Trillium ovatum is often found growing in coniferous and mixed coniferous-deciduous forests, in and around alder thickets and shrubs.[18] Along the California coast, it is commonly found under coast redwood and mixed evergreen forest.[6] At Lolo Pass, Montana, it grows under spruce and Douglas fir in ravines along mountain streams.[22]
Flowers bloom late February in the southern part of its range, and in March or April elsewhere. Citizen science observations of flowering plants of this species peak during the first week of April.[23] For comparison, when Trillium grandiflorum is fully open in eastern North America, T. ovatum is already fading in western North America. Apparently T. ovatum lacks sufficient winter hardiness to flourish east of the continental divide.[8][24]
The life-cycle stages of T. ovatum include a cotyledon stage, a one-leaf vegetative stage, a three-leaf vegetative (juvenile) stage, a three-leaf reproductive (flowering) stage, and a three-leaf nonflowering regressive stage. An example of the latter involves a transition from the three-leaf flowering stage to a three-leaf nonflowering regressive stage. Approximately one of every four reproductive plants regresses to a nonflowering state in any given year.[25] Under the right conditions, individuals may undergo extended dormancy, that is, they may cease above-ground growth for one or more years. In western Montana, dormancy was observed in all adult stage classes, with most plants returning to above ground status in a year or two, although some plants exhibited dormancy for 3–5 years.[26]
Trillium ovatum, the Pacific trillium, also known as the western wakerobin, western white trillium, or western trillium, is a species of flowering plant in the family Melanthiaceae. It is found in western North America, from southern British Columbia and the tip of southwestern Alberta to central California, east to Idaho and western Montana. There is an isolated population in northern Colorado and southern Wyoming.
T. ovatum is the most widespread and abundant trillium in western North America. It is the only pedicellate-flowered Trillium species found within its range. The type specimen for this species was gathered by Meriwether Lewis in 1806 along the Columbia River during the return trip of the Lewis and Clark Expedition.
